The present invention relates to multi-channel headphones for use in reproducing sound in an atmosphere of intimacy and privacy for individuals, and more particularly, to multi-channel headphones capable of reproducing 3 dimensional (3-D) sound with at least two speaker units for each ear piece.
With the development of personal computer (PC) based multimedia and digital communications technologies, the demand for headphones, earphones or headsets, which are suitable for entertainments such as seeing movies and listening music, and capable of providing improved virtual reality, gaming simulation, chatting or Internet telephony services, is sharply increasing.
To implement more enjoyable 3-D image based virtual reality simulations, reproduction of 3-D sound or at least almost 3-D sound is an inevitable necessity. Among a number of functions provided by PCs, multimedia and digital telecommunications functions whose importance is increasing are based on image and sound related technology. With the advance in image related technology, for example, associated with graphic cards or displays, high quality images become available for the customer. Also, many approaches have been used to provide more impressive 3-D sound. As a result of the efforts, there are xe2x80x9csurroundxe2x80x9d sound systems capable of providing spatial effects with 4 speakers, two more than a conventional stereo system, arranged to create sound fields in the front and rear directions, and the 5.1-channel system with 6 speaker units: four main speakers arranged in front left, front right, rear left and rear right around the listener, one central signal speaker for creating a phantom center image, and an woofer for providing non-directional low-frequency content to reinforce the sounds from the main speakers with bass.
The performance of sound cards has been greatly improved. However, sound related technique applications are quietly behind the applications of image related technologies. One main reason for this lies in the small size of headphones. For 3-D sound reproduction, a wide space is required to arrange at least four speakers spaced apart from each other. However, speaker enclosures for headphones are too small to receive two or more speaker units therein.
Korean Patent Laid-open Publication No. 78-399 and Korean Utility Model Laid-open Publication No. 1998-058453 disclose a variety of arrangements of speaker units within each ear piece of headphones. Korean Patent No. 124394 also discloses alternative arrangements of a plurality of speaker units using movable supports on a baffle to provide high-quality sound, like using more than 5 channels, with variable timbre. For these conventional configurations of multi-channel headphones, a closed type speaker housing pair that completely surrounds the listeners ears, like conventional stereo headphones, is adopted, each of which receives two or more speaker units for emanating sound from different channels.
The location of a sound source can be perceived a difference in phase of acoustic waves as well as a difference in acoustic intensity sensed by the listener""s ear. Although existing stereo headphones are successful in producing a binaural effect with two separate R- and L-channel speakers, which enables the listener to perceive the location of a sound source, stereo headphones are not suitable for reproducing 3-D sound, which needs more than two speaker units for each ear piece.
If two or more speaker units are mounted in one small housing of conventional headphones, sound waves emanating from the discrete speaker units reflect from the interior wall of the housing, causing interference, thereby smearing phases and deteriorating a spatial effect. The most disruptive effect is the generation of noise due to resonance within the small housing. Accordingly, the spatial and binaural effects are degraded, localizing the sound image over the listeners head. In this case, the listener cannot experience 3D sound and may not even be able to discriminate which speaker units sounds originate from.
To solve the problems, it is an object of the present invention to provide open-style multi-channel headphones, in which at least two enclosures are provided for each ear piece, and at least two speaker units are mounted in each of the enclosures, so that sound from each discrete channel can be reproduced intact with accurate phase.
It is another object of the present invention to provide multi-channel headphones designed in consideration of the reverberation and a phantom image that are necessary for spatial 3-D sound effect.
It is still another object of the present invention to provide multi-channel headphones capable of effectively producing 3-D sound, which can be reproduced with 5 or more channels, with just four speaker units: two for the left side and two for the right side, in which the sound transmission system is optimized for each of the speaker units.
To achieve the objects of the present invention, there is provided multi-channel headphones comprising: at least two speaker units for each ear piece, each for generating distinct sounds from multiple channels; and at least two enclosures in each of which each of the at least two speaker units are installed. The multi-channel headphones can prevent interference of sound waves from different channels.
It is preferable that the at least two enclosures are arranged spaced apart from each other in the front and rear around the listener""s ear, and the multi-channel headphones further comprises a sound guide portion for each of the at least two enclosures, the sound guide portion for guiding the sound emanating from the corresponding speaker unit into the listener""s ear. The multi-channel headphones can provide a sufficient reverberation effect during traveling of sound waves along the sound guide portion. In this case, it is more preferable that each of the at least two enclosures further comprises a sound reflection plate extending from the end of the corresponding sound guide portion, the sound reflection plate being tilted such that the sound reflected by the sound reflection plate goes toward the listener""s auricle.
It is preferable that the multi-channel headphones further comprise a plurality of guide ribs on the interior surface of each of the sound guide portions to create a plurality of sound passages. It is preferable that a number of projections are regularly or irregularly formed on the interior surfaces of the sound guide portions and sound reflection plates, to scatter the sounds.
The sound reflection plate of the front enclosure is positioned around the upper portion of the listeners ear, and the sound reflection plate of the rear enclosure is positioned around the lower portion of the listener""s ear, such that the sound waves reflected by the sound reflection plates go toward the listener""s auricle. The sound reflection plate of the rear enclosure induces diffraction of sound from the rear speaker unit. The resonant portion of the rear enclosure is expanded for sound amplification.